Carburetor



Jan. 26, 1932.

Filed Aug 2 Sheets-Sheet l I i: 4o 3 i P52 ..39 5 I X\ 13 6 i l l 9' 6ll fffi- 7 5h11' '::::::i/ 1 l l i l l l 2s g kas 2023 I l 3o FRED A.KOMMER INVENTOR ATTORNEY Jan. 26, .1932. F A KOVIMER 1,842,475I

GARBURETOR Filed Aug. 9, 1929 2 Sheets-Sheet 2 FRED A. KOMMER INVENTQRATTORNEY .a to be concentrated on the i'uel jets.

Patented Jan. 26, 193

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anni, assren'on ro marron, or sfr. nrs, Massenet, a eonrorron or a s i.

TER UBUTR COF'- UBURETR application led linguist t, W29. Serial No.384,572..

'llhis invention relates to improvements in carburetors,.andparticularly to the provision of means in a carburetor for producing arich mixture suitable for starting and warminge up purposes.

llt is very desirable in the use ot automotive engines to provide acarburetor having alr How passages ot fixed area for normal op eration,tor the provision of an open valve la operated by suction necessarilycauses a drag le in extreme low speed operation., for the air tends topass through the carburetorw without `lifting any tuel at all., it therate of How is low enough.

lt 'is customary in plain tube carburetors 2o to provide a Howrestricting valve to be-located near the air inlet to cause the suctionThis valve is usually manually operated and used only for starting. itssoon as the engine starts to run under its own power, the valve must beslightly open to permit the engine to warm up properly. @wing to theconsiderable change in speed from the starting speed to running speed,or, in other words, the change from the speed at whichthe engine isoperated by the starter and that at which it is operated under its ownpower, considerable difficulty is eX- perienced in adjusting the valvein such a manner that a sufficient flow restriction will be presented atcranking speed without overand warming up, the throttle valve must beadjusted to a slightly open position when the choke valve is closed, andthis involves 'delicate adjustments and expensive connections betweenthe choke and throttle.

llt is an object of this invention to provide a carburetor of the plaintube type as far as normal operation is concerned, having a singlemanually operated choke valve to be used in starting and having means toautomatical- 0 ly adjust the amount of air which is permitted to enterwithout the necessity of manually changing the position of the chokevalve.

lt is a further-object of this invention to produce a carburetor havinga choke valve for restricting the admissionof air for starting purposesand having means independent of the choke valve for permitting entranceot additional air as soon as the engine begins to run under its ownpower.

llt is a further object of this invention to produce a carburetor havingmeans tor adyustmentf to produce a suitable mixture for starting andalso having means to permit the warming up of the engine after it startsto run under its own power, the warming up means being independent ofthe position of the throttle valve. f

llt is a further object of this invention to produce a carburetor havinga 'choke valve and having means operated by said choke valve andindependent of the throttle valve for producing. a starting andwarming-up mlxture.

llt is a further object of this invention to produce a carburetor inwhich the necessity ot connecting the throttle and choke will beobviated.

@ther objects of the invention will appear from the followingspecification and the accompanying drawings, referring to which:

Figure l is a sectional elevation of a carburetor having my inventionapplied thereto.I

Figure 2 is an elevation of the opposite side ofthe carburetor showingFigure l, with parts broken away for clearer illustration of others.

Figure 3l is an end view of the carburetor shown in Figures l and 2,with parts broken away for better illustration of others.

Figure 4 is a plan view ot the carburetor shown in Figures 1, 2, and 3.

The reference numeral 1 indicates a casting forming the main body of thecarburetor.

ternal combustion engine. The `body/memf ber l is formed with a seat 5having a bore 6 from the air chamber 8 and receiving a mixture of fueland air from a standpipe forming a primary mixing chamber 14. At theside of the air chamber, opposite the main f inlet 9, an opening 16leading from the air chamber to the atmosphere is formed. This openingis controlled by a suction operated valve 17v seating on an annularsurface 18 in they main body member. The valve is carried on a stem 19which is slidably carried by the supporting member 20. A coiled spring21 is provided forv seating the valve and this is retained by suitablemeans, such as a wash er, which is held in place by a cotter pin 22 0rother suitable ,means The supporting member is provided with flanges 23and is retained in position by screws 24. These screws also serve tohold a suitable shield 25 to prevent the entrance of large particles offoreign matter to the carburetor.

The standpipe 15 is provided with a flange 26 which is threaded into adepression or well 27 in the lower part of the air chamber. Thestandpipe 15 comprises the mixing chamber 14 which, in the presentinstance, is formed as a cylindrical passageway, and the primary venturi28 at the lower end of the primary mixing chamber, and one or more airports 29 to permit air to enter from the air chamber at the lower end ofthe venturi 28. A small bleed port 30 permits the passage of air fromthe air chamber through the flange 26 to the accelerating well 31.

The fuel for the main supply under normal operating conditions issupplied from the float bowl 32 which is attached to the carburetor by anut 33. The fuel is supplied to this chamber by any suitable means (notshown) and maintained at a suitable level by the usual float and floatvalve construction. This is very well known in the art and is not shown.The fuel enters the Vport 35 from the float chamber, the bore 34 beingplugged, as shown. A main nozzle 36 is threaded into the body member andarranged to receive fuel from the port 35, as shown.

The fuel from the port 35 enters the accelerating well which surroundsthe main nozzle and also flows to the chamber 37 which supplies theidling tube 38. This idling tube delivers fuel to a bore 39 in themember 2. An adjusting screw 40 having an air admission port 41 controlsthe admission of `air to v the upper part of the bore-39, andthe`mixture is discharged at the port 42 in the passagemeagre way 10adjacent the edge of the throttle 11 when it is in closed position.

A choke valve 43 is attached to a shaft 44 which is pivoted in suitablebearings in the air inlet passageway 9. This shaft is manually operableby any suitable means, such as the crank 45, which may be attached to aBowden wire, or other device, so that it may be operated from the dashof the car. By opening and closing the valve 43, the admission of airthrough the main air inlet to the air chamber can be governed.

A passageway 46 is formed in the main body member in such a manner as tocommunicate with the fuel in the bowl 32 and with a transverselyvextending passageway 47 which, in turn, communicates through a secondupwardly extending passageway 48 with a second transverse passage 49.From the end of the passage 49 a third upwardly extending passage 50extends to the seat 5 where it is considerably enlarged as at 51. Thebody member 2 is provided with an angular upwardly extending passage 52having an enlarged portion 53 at its lower end to communicate with theopening 51. The pasl sageway 52 terminates in an outlet port 54 abovethe throttle 11.

The shaft 44 of the choke valve 43 is provided with a transversepassageway 55 registering with the bore 49, as shown in Figure A2. Thispassageway 55 comprises a valve for turning on oro the flow of fluidfrom the fuel bowl to the suction chamber in the passageway 10 above thethrottle. Suitable plugs 56, 57, and 58 being provided to close the endsof the passageways 48, 49, and 47 respectively. A direct communicationbetween the suction chamber and the float chamber is established byclosing the choke valve 43 so that raw fuel will be drawn into thesuction chamber. It will be understood that there may be some leakage ofair into this passageway, especially around the shaft 44, withoutseriously interfering with the conveyance of the fuel to the suctionchamber.

i It will be understood that when the choke valve 43 is openthe valve 55will be closed, and vice Versa.

' The operation of the device is as follows:

The carburetor being attached to the intake manifold of an internalcombustion engine, and it being desired to start the engine, the valve43 is closed, thereby opening the Valve 55. The throttle of the engineis en-V tirely closed, except for such leakage as may occur around theport 42, or which may occur through auch clearances as may be present inthe normal idling position of the throttle. Thus, there is a doubleclosure against the admission of air to the suction chamber when theengine is rotated by the starter, the throttle valve providing oneclosure, and the valves 43 and 17' providing another. Atmosphericpressure exists above 1 'lll the level of the fuel in the float'chamber,a

vent 59 being provided for that purpose.v

When the engine is operated by the cranking means, the suction producedin the suction chamber will thus draw raw fuel through the passageway46-52 from the fuel bowl to the suction chamber. This raw fuel will mixwith such air as enters by leakage and form a suitable mixture forstarting the engine at low temperatures.

As soon as the engine starts to run under its own power, therequirements for air are increased and the leakage around the throttleValve, particularly at the port 42, from the air chamber, produce areduced pressure in the air chamber which opens valve'17 ,permitting theentrance of additional air to the carburetor. This air leaks around thethrottle valve into the suction chamber along with air entering theports 4l and thus forms a mixture suitable for operating the engine at aspeed suitable for warming up. When the engine has become sufficientlywarm, the choke valve 43 is opened, thereby closing the valve 55 andpreventing the How of any more fuel to the tube 4654 in the suctionchamber after which the carburetor continues to operate in the usualmanner by drawing fuel from the main nozzle 36 and/or the idling port42, ac-

cording to the speeds and loads at which the engine is operating.

l claim:

l. lna plain tube carburetor, means forming a mixing conduit, a throttlevalve and a choke valve in said conduit, means operable by closing saidchoke valve to conduct raw fuel to saidL conduit at the suction side ofsaid throttle., and a relief valve mounted in a wall of said conduit andadapted to open bv suction to permit air to flow into said conduitbetween said throttleand said choke, said relief valve being held inclosed position at all times, except when said choke valve is closed.

2. ln a carburetor, means forming a mixing conduit,.said conduit beingadapted for attachment to the intake manifold of an internal combustionengine, a throttle valve adjacent the outlet end of said conduit, and achoke valve adjacent the inlet end, a fuel chamber, a passageway leadingfrom said fuel chamber to a point in said conduit between the throttleand the outlet, a valve in said passageway, a connection forsimultaneously operating said last named valve and said choke valve, anda relief valve between the choke and the throttle for admitting Iaironly when said choke valve is closed.

3. lln a carburetor, a throttle valve, a choke valve, means operated bysaid choke valve for supplying raw fuel to said carburetor at thesuction side of the throttle valve, and a relief valve operated bysuction to permit the entrance of air into said carburetor, said reliefvalve being held in closed position at all times, except when said chokevalve is closed. f

In a carburetor, means forming an a1r,

4. chamber, means forming an outlet for said air chamber, comprising amixingI conduit, a Vnormally open main airinlet of sufficient size tosupply all the air necessary to operate said carburetor at maximumcapacity, and a normally closed auxiliary inlet for said air chamber,means for supplying fuel to said passageway at a point outside of thethrottle, a valve for controlling said main air inlet, and meansconnected to said valve to central said fuel supply conduit.

5. ln a carburetor, a main air inlet of sufficient capacity to supplyall the air necessary to operate-said carburetor at maximum capacity, anauxiliary air inlet,'a mixture outlet, a throttle controlling thepassage of mixture through said outlet, a fuel bowl, means comprisingvalves for controlling said air inlets, a connection from said fuel bowlto the mixture outlet, and means operated by one of-said valves forcontrolling said connection.

ln testimony whereof, ll aix my signature this 2ndvday of July, 1929..

FRED A. KMMER.

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